Signaling system



M. C. POYLO SIGNALING SYSTEM Aug. 30, 1949.

2 Sheets-Sheet l Filed June 27, 1945 ug. 30, 1949. M. c. Po-YLoSIGNALING SYSTEM Filed June 27, 1945 2 Sheets-Sheet 2 l, f7/@ggfATM/FA/EY Patentecl Aug. 30, 1949 lSIGNALING SYSTEM Michel C. Poylo, NewYork, N. Y., assignor to Federal Telephone and Radio Corporation, NewYork, N. Y., a corporation of Delaware Application June 27, 1945, SerialNo. 601,799

4 Claims.

This invention relates to new and useful improvements in traindispatching systems, and more particularly to a system adapted forcombination with a railroad communication system such, for example, asdisclosed in the copending application of E. M. Deloraine (37), SerialNo. 531,851, filed April 20, 1944.

It is the object of the present invention to devise an arrangement forproviding at all times at a dispatchers station and/or on board anytrain a record of the position and/or speed of one or more trains.

Another object of the invention is to provide means on a moving vehicle,such as a railroad train, to provide a source of signals whereby sub-1stantially the instantaneous location or the vehicle along a given pathmay be readily determined or indicated.

The nature of the invention will more clearly appear from the followingdescription of an embodiment thereof, the specific means here disclosedbeing subject to many variations as will be obvious to those skilled inthe art.

In the drawings, Fig. 1 illustrates the general scheme of a railroadcommunication system with which the dispatchers signaling station iscombined;

Fig. 2 illustrates as much of a train radio transmitter as is necessaryfor an understanding of the invention;

Fig. 3 diagrammatically illustrates a portion of the receiver at thedispatchers station arranged to receive signals from the traintransmitters to record the position of the train;

Fig. 4 is a graph of the pulses transmitted from the dispatchersstation;

Fig. 5 is a block diagram of the receiver provided on each train toreceive signals from the dispatchers station;

Fig. 6 is a curve of the synchronizing or marker pulses sent out fromthe synchronizing station; and

Fig. 7 is a block diagram of the receiver and transmitter on each trainadapted to receive from the synchronizing station and send to thedispatchers station.

In Fig. 1 is shown a dispatchers station 1 from which radio signals maybe sent out on carrier frequency f1 via directional antenna 2 and atwhich radio signals may be received on carrier frequency f2 viadirectional antenna 3. Preferably the system utilizes an ultra-highfrequency or microwave carrier on which intelligence can be transmittedin a plurality of channels by means of time-modulated pulses. As is wellknown and 2 shown, for example, in British Patent No. 587,941, filed May26, 1944 and United States Patent No. 2,445,775, the pulses belonging toeach channel of' intelligence follow one another, and a group or seriesof such pulses representing the different successive channels isseparated from the next series by a synchronizing or marker pulse havinga distinguishing characteristic, e. g., greater width than the width ofthe intelligence pulses.

Fig. 4 shows a graph of the emission from the dispatchers transmittingstation I. In this graph, m designates the marker pulses and a, b, c, d,e, j, the relatively narrow channel pulses. The positions of the channelpulses a-f will be varied with respect to the marker pulse in acucordance with the modulation impressed thereon.

The modulated carrier can be relayed along the railroad tracks 4, 5which it is desired to supervise by means of relay stations 6, 'I and`8.

At the other end of the system is a synchronizing station 9 wheresynchronizing signals may be sent through directional antenna i Isuperimposed on carrier frequency f2. These serve to segregate theseries of channel pulses which may be sent on f2 from station 9 and anyone of the trains I5, I and I'I and relayed by means of relay stationsI2, I3 and I4 to the dispatchers station l.

The means on each train for receiving and demodulating the signals sentto it from the dispatchers station I may be of any well known design. Asindicated in Fig. 5 they may consist of a receiver R adapted to receivesignals on frequency f1. This receiver controls a 4pulse width separatorand shaper S of known character for example, of the type disclosed inUnited States Patent Number 2,440,278 which is adapted to be operated bythe marker pulses m only. A delay network N of well known type connectedwith the separator-Shaper S introduces a suiicient time delay betweenthe marker pulse timing and a particular channel timing like channel C,for example, so that the demodulator D, of the type shown in BritishPatent No. 587,941 or in United States Patent Number 2,199,634 will beconditioned only for action on the desired channel signals, e. g., cwhich is meant for the particular train on which the receiver islocated.

Each of the moving trains, e. g., I5, i6 and Il, is adapted to receivesignals belonging to a particular channel on frequencies f1 and f2 andto transmit signals to the dispatchers station on a predeterminedchannel at frequency f2. The sending is accomplished on a train by meansof a transmitter I8 modulated by means of a modulato the modulator I9shown in Fig. 2 where theY signaling pulse is superimposed on thecarrier f2 in its proper phase relation to the marker pulses ml. Thissignal pulse is modulated from an audio source in a manner to bepresently described and shown in greater detail in Fig. 2 andthemodulated signal pulse together with the marker pulse ml are transmittedby the transmitter I8 from the train on carrier frequency f2 towards thedispatchers station I.

In addi-tionl tol modulation by a microphone 23 the transmitter I'B-on atrain may be modulated also by' agenerator ZI adapted to generate a1350"-cycie signalv or a generator 22 adapted to generate a 100f-cyclesignal. Both generated signals' being belowv the'range of' audibility,they willnot interfere withspeech transmission on the channel assignedto the-train.

Number23 illustrates a rotatable means e. g., the axleon which a specialwheel or a non-drive ing wheel of the locomotive or other car ismounted; Through sui-table coupling 24 the clockwise rotationy of theaxle 23 is transmitted to a cam 25 atY a= certain` ratio, and through asuitable coupling' 2S- the' counterclockwise rotation of the axle 23irs-transmitted to the cam 27. Depending; therefore, whetherv the traingoes forward of' backward, the cam 25 will be rotated in a clockwisedirection periodically to close a contact 28, or the cam 21 will berotated in a counterclockwise direction periodicallyV to close a contact29. Whenever the contact 28 is closed the carrier is modulated by'a100-cycle and whenever contactZB is closed by a 150-cycle signal andtransmitted fromV the train. Thus, for each unit of length the train;travels forward, a 100-cycle signal is sent; and for each unit of lengththe train travels backwardga 150-cycle signal is sent. Assuming that thecircumference of a wheel mounted on aXle` 23' is ten feet and assuming atopspeedof 120 miles'per hour,l or 166 feet per second, one mightprovide a gear ratio of 8 to 1 to produce two impulses for every sixteenrevolutions thatV the` wheel may perform per second, or one impulseevery 83d feet. Thus, the position of the train maybe indicated within100 feet fora speed of" 120' miles per hour, although impulsesA willEle-sentVv only at the rate of two per secondi Each train? willretransmit on frequency f2 the pulses mi' together withV thesignal'pulse properly spacedtherefrom: Thefsignals will -be receivedatthe dispatchers station If, on antenna 3 in the usual interlacedchannel. pattern as shown for instance inFig. 4- for the-signals thatare transinittedzfromthe dispatchers station on frequency f1. Of.course, if no signalv is sent from a train towhich a channel is assignedthenthere will be no, pulse` in its. place The antenna isconnectedwitnthe known receiver means 33 adapted to receive anddemodulate the time-modulated pulses received.

Number 3I is an audio frequency output transformer on receiver 30conveying the intelligence received to a loudspeaker 32.' The 100 and150'- cycle pulses will pass through a low-pass lter 33 to two reeds 34and 35 connected in parallel with the lter, the reed 34 being tuned to100 and the reed 35 to 150 cycles. One or the other reed will be causedto vibrate its armature 36 and 3'I, respectively, to alter the magneticiield of permanent magnets 38 or 39 provided adjacent thereto;The'fimpulses so generated? are rectied and' amplified atL 40 and* 4I^,respectively; to operate stepping mechanisms 42 or 43, as the case maybe and are thus accumulatively registered onthecnrresponding steppingmechanisms. Any suitable arrangement may be provided at 42 and 43, e.g., a, pawl and ratchet arrangement of any well-knowntype as for examplethat shown in Fig. 'Tof Ui Si Patent to Lambot No. 1,072,474, grantedSeptember-9, 1913, to cause an indicator or recorder 44 which even maybe desired, to movel in one direction or the other in response to eachstep conveyed thereto from 42 or 43 thus indicating' at any momenttheposition of the train.` It' will beseenthereforethat the steppingmechanism willi take onestepl eachtime contact 28T or 29lisf'closedi,theemechanism asin other well known systems notbeing responsive to eachcycle of the 10'0 or 150 cycle'- modulation but being responsive to eachperiodici: su'chm'odulation.

The recorder may' take' anyf one of a number of forms. It may loe-falcounter which displays numerals indica-ting the dist-ance traveled bythe train (83 feet for" each" impulseA received in the above-assumedcase), or it may consist ofv a Abank. of lampseachof-fwhichis allotted'to a certainl pointr ofthe track and which lamps successively' light, orofastyluswhich draws a graph on a stripof: paper, etch., and may includesome. form' oi speed-indicator.l There willbe one such location recorderend speed indicator at the dispatchersstation' foreach train indicatingat all times its exa-ct' position and speed and it should beunderstoodthat; of course, each channel individually allotted" toa train, isseparated from the other channels already in the receiver.

In my reference to` traing it should be understood that this term isused in a broad sense as covering any' vehicle' that" is guided along agiven track. It will. also be clear that since instantaneous positioningof several trains are indicatedA substantially' simultaneously by thesignals transmitted along, the. track, such provide a goodanti-collision signaling system4 between trains.

WhileA I'have referred to station-9 as the source of synchronizingsignals, it will be clear that` the synchronizing signals may originateat the dis-V patchers. station IT if desired. It. will be clear thatmany other variations such as thev details of' the transmitting and"receivingA equipment of. Figs. 2 and 3, andY their combination withother apparatus may loe-made without departing from thel scope oftheinvention. For example, each train could` be equipped with a. receiverfor. receiving signals. transmittedY from another train and withV anindicator responsive tothe received signals.

I claim:

1'. In av signaling system, a dispatchers stationprovided with a.receiver to. receive on a carrier frequency signals forming. a pluralityof communication. channels, aplurality of trains movable, withfrespect.to saiddispatchers station each.

associated generators to modulate the transmitter on the train once foreach unit of distance travelled in one direction, means on each trainfor connecting the other generator there-at to modulate the transmitteron the train once for each unit of distance travelled in the oppositedirection, means at the dispatchers station selectively responsive tothe signals transmitted by said generators, and indicator means at saidstation controlled by the last mentioned means in one sense in responseto accumulated signals of one generator and in the opposite sense inresponse to accumulated signals from the other generator.

2. The signaling system according to claim 1, means for sending from acommon point channel synchronizing signals on said carrier, and means oneach train to receive and to send out by the associated transmitter saidsynchronizing signals together with the other signals generated on thetrain.

3. In a signaling system, a dispatchers station provided with a receiverto receive on a carrier frequency signals forming a plurality ofcommunication channels, a plurality of trains movH able with respect tosaid dispatchers station each provided with a transmitter to send onsaid carrier audio signals belonging to a predetermined channel, twodifferent generators of sub-audible frequency signals on each train,means on each train for connecting one of the associated generators tomodulate the transmitter on the train once for each unit of distancetraveled in one direction, means on each train for connecting the othergenerator there-at to modulate the transmitter on the train once foreach unit of distance traveled in the opposite direction, a low-passlter connected with the receiver at the dispatchers station, twofrequency responsive means connected With the low-pass filter, one tunedto the frequency of one and the other to the frequency of the other ofsaid generators, and a recorder con- 6 A trolled by one responsive meansin one sense and the other responsive means in the opposite sense.

4. In a signaling system, a dispatchers station provided with a receiverto receive on a carrier frequency time-modulated pulses belonging to aplurality of communication channels, a plurality of trains movable withrespect to said dispatchers station each provided with a transmitter tosend on said carrier pulses belonging to a predetermined channel tWodifferent generators of pulses of a frequency outside of the audiblerange on each train, means on each train for connecting one of theassociated generators to modulate the transmitter on 'the train once foreach unit of distance traveled in one direction, means on each train forconnecting the other generator there-at to modulate the transmitter onthe train once for each unit of distance traveled in the oppositedirection, means at the dispatchers station selectively responsive tothe signals transmitted by said generators, and an indicator means atsaid station, the last mentioned means operating in one sense inresponse to signals from one generator, and in the opposite sense inresponse to signals from the other generator.

MICHEL C. POYLO.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 253,442 Starr Feb. 7, 18821,072,474 Lambot Sept. 9, 1913 1,747,011 Alexanderson Feb. 11, 19301,993,497 Wells Mar. 5, 1935 2,089,639 Bedford Aug. 10, 1937 2,311,021Blumlein Feb. 16, 1943 2,363,416 Henroteau Nov. 21, 1944

